Sealing device



p 1942. H. HORNSCHUCH 2,297,302

SEALING DEVICE Filed June 22, 1940 mv NTOR HIS ATTORNEY pump.

Patented Sept. 29, 1942 SEALING nnv'rcn Harms Hornschuch', Easton, Pa., assignor to lngersoll ltand Company, New York, N. Y., a corporation of New Jersey Application June 22, 1940, Serial No. 341,843

2Claims.

This invention relates to a sealing device and, more particularly, to a seal adapted for use with a centrifugal pump and the like.

. The seal of the present invention comprises a pair of sealing members, movable longitudinally with respect to each other, which cooperate to valve a small amount of liquid therebetween to lubricate the sealing surfaces as one sealing member rotates with respect to the other. Or dinarily, the seal is arranged in the chamber intended to be sealed and, in order to retard the escape of liquid through the space between the sealing surfaces, the sealing members coact with the pump rotor to define a sealing fluid chamber to which sealing fluid is supplied.

In order to seal these two chambers from each other and prevent leakage of all liquid from the chamber to be sealed, except through the desired channel, spring-pressed plastic sealing elements are employed. The springs acting against the plastic elements are so arranged that they also serve to hold the sealing members in sealing relationship.

. In such an arrangement there may be wear of thesealing members and, since the members are movable longitudinally with respect to each other, occasions will arise when the plastic sealing elements will also become worn. Such wear must be compensated for and, accordingly, it is an object of the present invention to provide a sealing device wherein the component seals may be adjusted without disassembly-of the seal.

It is another object to provide a sealing device wherein the sealing liquid can only escape through a predetermined channel to lubricate the I sealing surfaces, 7

Another object is to provide a sealing device wherein the springs normally take up the wear of the sealing surfaces and external means are employed to compensate for excessive wear,

A further object is to provide a sealing device which is simple in construction yet strong and durable, which will effectively seal liquid'in the pump and in which perfect alignment of the sealing surfaces is unnecessary.

These and other objects will be apparent from.

the following description of which the drawing forms a part and wherein the device of themes-'- ent invention is shown as applied to a centrifugal In the drawing, the sealing device, generally indicated at I; is shown as applied to a pump.

' generally indicated at 3. The pump, being acentrifug'al pump, comprises a shaft 5 to which is keyed, by key I an impeller 9. The impeller 55 into sealing engagement with the sleeve 2! and 9, as shown, is an initial stage impeller and, consequently, the impeller chamber is subjected to the inlet pressure of the fluid pumped.

Loosely surrounding the end of shaft 5 is a stufling box ll. Theouter end of the bore, or chamber, l3 formed in the stufling box is closed by a supporting member, or cover plate, I5, having an annular skirt ll, extending into the chamber I3 The cover I5 is adjustably secured on the stumng box II by bolts 19 and by this means the distance the skirt I'l extends into the chamber l3 may be controlled by moving the cover toward or away from the stufllng box.

On the portion of the shaft 5, seating against the impeller 9. and extending into chamber i3, is a sleeve 2| which is secured to the shaft by the key-I. A nut 23 is threaded on the shaft so that it lies within the bore of the cover l5 and presses the sleeve 2| firmly against the impeller member 25 provided with a flange 21 on which is a sealing surface 29. This member surrounds and is spaced from the, sleeve 2| at a point near the shoulder 3| which is formed on the sleeve. A second annular sealing member 33, bearing on the skirt I1 and spaced from the sleeve 2!, has a sealing surface 35 which cooperates-with the surface 29 to effect a seal for chamber l3 and through which sufllcient fluid may be valved to. lubricate the surfaces and prevent excessive wear.

Near the impeller 9 and mounted'on the stuffing box I I is a spacer 31 which deflnes an annular passage 39 from the impeller chamber to the chamber I 3, By means of this passage, fluid at the initial pressure of the pump may be intro- 'ducedinto-the chamber It thus subjecting the plunger ring are springs 5| to constah'tlyuige the plunger rlnglS against the packiiig'jfi'ing 43 to hold it against the surface ll. Th packing ring 43 is considerably larger than thesurface 4| and, consequently, a portion thereof is pressed Within the chamber I3 is an annular sealing thus effects a seal between the annular member 25 and the sleeve 2| to prevent escape of fluid from chamber |3 therebetween.

The plunger ring 45 extends completely around the sleeve 2| and any desired number of stems 41 and springs 5| may be employed to hold the packing ring 43 securely in place, although only two have been shown in the drawing. Likewise, a series of lugs 53, corresponding in number to the number of stems 41 and springs 5| provided, are formed on the plunger ring 45 which extend into slots 55 formed in the outer wall of the annular member 25.

Since the sleeve 2| is keyed to the shaft 5, the sleeve will rotate with the rotor and, likewise, the stems 41, springs 5|, the plunger ring 45 and the packing ring 33 will also rotate. Consequently,

the annular member 25 should be rotated and to face 51, also concave in contour, is formed on the skirt I! in which rests another plastic cup packing ring 59. A second plunger ring 6|, having stems 63 extending into the bores 65 provided in the annular sealing member 33, is heldagainst the plastic packing cup ring 59 by springs 61 encircling stems 63 and compressed between the.

plunger ring BI and the annular sealing member 33. Normally, the springs 61 not only act to hold the plunger ring 6| against the plastic cup packing ring 59 but also to urge sealing surface 35 into sea-ling engagement with' the sealing surface 29. I

The annular sealing member 33 has slots 69, corresponding in shape to the slots 55 in the annular sealing member 25, into which extend pins ll The pins H are formed on screws 13 threadedly engaging the skirt IT. The pins II and slots 69 serve to limit the movement of the annular sealing member 33 away from the annular sealing member 25 and also prevent rotation ofthe annular sealing member 33 with respect to the skirt I! which might be induced by the rotation of the annular sealing member. 25. In this construction also any desirable number of stems 53, springs 61, pins 1| and slots 69 may be employed.

' In the cover I5 is a bore, or conduit, 15 connected to the pipe 11 through which sealing fluid may be supplied. Ordinarily, any liquid passing between the sealing surfaces 29 and 35 would pass through the annular space 19 between the annular sealing member 33 and the sleeve 2| and escape. In order to prevent this and minimize the flow of liquid through the seal, a smothering fluid is introduced through bore 15 which communicates with the space II.

It will thus be seen that a seal has been provided in which separate springs 5| and 61 hold the annular sealing members 25 and 33 in seal-' 1. A sealing device for a rotary shaft including.

a sleeve on the shaft having a shoulder, a ring shaped sealing member fitting closely the larger diameter of the sleeve and sealed thereat, having an inwardly extending flange at the shoulder, a

second sealing member about the sleeve, both said sealing members having cooperating sealing and bearing end surfaces and being adapted to move longitudinally with respect to the shaft, and individual resilient means for the sealing members acting in opposition to each other to actuate the said members endwise of the shaft for holding said end surfaces in contact.

2. A sealing device for a rotary shaft including a sleeve on the shaft having a shoulder, a ring shaped sealing member fitting closely the larger diameter of the sleeve and having an inwardly extending flange at the shoulder, a means to seal said member including a packing ring, a gland to compress the packing, springs bearing against the gland, and means to couple the sleeve with said member, a second sealing member about the sleeve, both said sealing members having cooperating sealing and bearing end surfaces, and individual resilient means for the sealing members acting in opposition to each other to actuate the said members endwise of the shaft for holding said end surfaces in contact.

HANNS HORNSCHUCH. 

